Relationship among glass-forming ability, fragility, and short-range bond ordering of liquids
Relationship among glass-forming ability, fragility, and short-range bond ordering of liquids
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DOI：
10.1016/j.jnoncrysol.2005.01.070
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发表时间：
2005-04
影响因子：
3.5
通讯作者：
Hajime Tanaka
中科院分区：
文献类型：
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作者：
Hajime Tanaka
玻璃形成能力的特点是我们如何容易地避免结晶，从而使玻璃态的材料从其液态冷却。其定量测量由临界冷却速率给出，临界冷却速率是形成玻璃或避免晶体成核所需的最小冷却速率。在这里，我们考虑什么物理因素控制液体的玻璃形成能力。我们认为，短程键序，这是诱导的相互作用势的选择性的一部分，导致挫折对结晶，并有助于玻璃化，如果其局部对称性是不一致的平衡晶体。基于这一物理图象，我们提出，在液体中的短程键有序的程度应该是一个新的额外的物理因素控制的玻璃形成能力。根据我们的模型，它也是脆性的一个控制因素，脆性的特征是粘度在冷却时急剧增加。这表明玻璃形成能力和脆性之间存在负相关关系。根据我们的模型还讨论了金属玻璃形成体的玻璃形成能力与准晶体形成能力之间的密切关系。
Glass-forming ability characterizes how easily we can avoid crystallization and thus make a glassy state of material from its liquid state upon cooling. Its quantitative measure is given by the critical cooling rate, which is the minimum cooling rate required for the formation of glass, or the avoidance of crystal nucleation. Here we consider what physical factors control the glass-forming ability of a liquid. We argue that short-range bond ordering, which is induced by a symmetry-selective part of the interaction potential, causes frustration against crystallization and helps vitrification if its local symmetry is not consistent with that of the equilibrium crystal. Based on this physical picture, we propose that the degree of short-range bond ordering in a liquid should be a new additional physical factor controlling the glass-forming ability. According to our model, it is also a controlling factor of the fragility, which characterizes how steeply viscosity increases upon cooling. This picture suggests a negative correlation between the glass-forming ability and the fragility. The close relationship between the glass-forming ability and the quasicrystal-forming ability in metallic glass formers is also discussed in the light of our model.